International Scholarly Research Notices

Review Article

Endometriosis and Ovarian Cancer: A Systematic Review

Table 2

Summary the types, sample size, followup time, confounding factors, and limitation of each one of the eight studies included in our review.


Name of study	Type	Mean of followup (years)	Size of endometriosis cohort	Ovarian cancer cases identified in the cohort	Confounding factors considered	Main limitations

Aris 2010, Canada [17]	Retrospective cross-sectional	9	2521	41	Age, pregnancies, family history, race, oral contraceptive, tubal ligation, hysterectomy and breastfeeding	Retrospective collection of data using a coded computerised system. Selection bias
Borgfeldt and Andolf 2004, Sweden. [18]	Case-control	10	28,163	81	Age and parity	Use of cohort of women discharged from hospital with a diagnosis of endometriosis. This may lead to including women with moderate and severe endometriosis (hospital stay patients) without minimal and mild cases. This may overestimate the risk ratio. Selection bias.
Brinton et al. 1997, Sweden. [19]	Retrospective cohort study	11.4	20,686	29	Age and length of history of endometriosis
Melin et al. 2006, Sweden. [20]	Retrospective cohort study	12.7	64,492	122	Age and type of surgery performed.
Melin et al. 2007, Sweden. [21]	Retrospective cohort study	13.4	63 630	134	Age, parity, and type of surgery performed
Modugno et al. 2004, USA. [22]	Case-control			177	Age, parity, oral contraceptive use, tubal ligation, family history of ovarian cancer, and study site, gynaecological surgical procedures	Recall and selection bias, as the authors pooled data on the history of endometriosis reported by patients.
Ness et al. 2000. USA. [23]	Case-control			66	Age, history of ovarian cancer, parity, breastfeeding, type and length of each contraceptive, tubal ligation, hysterectomy, ovarian operations.	Data was collected by case interviews. Recall bias. Low participation rates among cases and controls.
Olsen et al. 2002, USA [24]	Prospective cohort study.	13	1,392	3	Age, education, marital status, alcohol intake, physical activity, smoking, parity, oral contraceptive use, HRT, history of hysterectomy or dilatation and curettage, BMI and waist to hip ratio.	Reliance on self-reports of endometriosis in this cohort (a questionnaire). Recall bias. The number of women who developed ovarian cancer is quite limited.